1. Field of the Invention
Method of providing a rotating cutting tool with lubricating coolant, as well as a tool and a tool holder for carrying out the method.
2. Background Information
One problem encountered in the cutting of work pieces, and of metal work pieces in particular, is that the boring tool, such as a drill, reamer or a rotating tool in general (the following description relates in particular to drills), heats up during the cutting process along with the material of which the work piece is made. In automatic mass production operations in particular, cooling and lubrication using a lubricating coolant (designated a "lubricant" below) is therefore necessary. In wet machining processes, a large excess of liquid lubricant is introduced into the hole as it is being drilled. This type of lubricating and cooling action entails relatively high costs for equipment, not to mention the costs of the lubricant supply, the necessary cleaning, etc. In drilling operations, moreover, it is not always possible to deliver the lubricant directly into the hole being drilled. Therefore, lubricating systems are used in which the lubricant is transported by means of transport devices via the spindle of a drilling machine and at least one lubricant channel in the drill to the site of the drilling. The site of the drilling is approximately in the vicinity of the major cutting edges or the chip faces of the drill. In these known lubrication systems a relatively large quantity of lubricant is required, because the supply lines which lead from the supply device to the drill or to the spindle of the drill must be filled with lubricant. In addition, a precise and controlled dispensing of small quantities of lubricant is very difficult to achieve using the conventional delivery devices.